1. Field of the Invention
This invention relates to a switch input device for an operation panel apparatus, a keyboard apparatus or the like incorporated in various kinds of electronic instruments.
2. Related Background Art
In recent years, facsimile apparatus or the like as electronic instruments incorporating operation panel apparatuses therein have come to be provided with various high functions and the tendency thereof toward multiple functions has been progressing. With such a tendency toward high functions and multiple functions, the number of operation input switches on an operation panel is in a tendency toward an increase. This increase in the number of switches leads to the smaller size of the individual switches, which in turn leads to a problem such as the aggravated operability or the difficulty with which the dispositions of the many switches are remembered and a desired switch is found out. There is also a problem that the indications of the input functions of the switches are so numerous that it difficult to discriminate between them or to make entries.
So, there is adopted a construction in which an operation input switch is endowed with a plurality of input functions which are adapted to be changed over. In such system (disclosed, for example, in FIG. 1 of Japanese Patent Application Laid-Open No. 56-140457), a cover having apertures in which the key tops of individual switches fit is openably provided over the group of switches and the input functions may be changed over by opening or closing the cover. In this case, the indications of the plurality of input functions of the individual switches are discretely provided on the cover and the surface or the like of an operation panel which underlies the cover. By doing so, the input functions of the switches as well as the indications of the functions can be changed over in response to the opening or closing of the cover. Thus, there is afforded a margin of space for the indications of the functions of each switch, and the indications of the functions become easy to discriminate between or make entries.
However, such a construction in which the change-over of the input functions of each switch and the indications of the functions is effected through the cover is not free of a case where when the cover is opened, the cover protrudes onto the operation panel and interferes with the operation of the apparatus. For example, in a facsimile apparatus, there is a problem that when the cover is in its opened state, it hinders the operator from handling originals to be transmitted. There is also a problem that the opened state of the cover provides ugly appearances.